I'm convinced there would be a way of working from the original tapes.
Much like they were able to colourise from black and white telecene(?).
There must/may be some portion of the tape that doesn't magnitse correctly each time.
Experts said no, but has anyone actually tried?
For example governments/companies like recording off old tapes to "preserve them" digitally. 
However, they just use a video player to do so, saving the machines output.
I would think saving raw tape "data" directly from the head, prior to any manipulation by a decades old device would be more logical.
Then in years to come a cyber player could be created to create a higher quality out put.
But no. We are being left with "old video" preserved recordings.
By getting"raw data" a future cyber player could perhaps detect previous recordings, to whatever degree.